This invention relates to the removal of screw-off closures from containers. More particularly, this invention relates to the removal of screw-off closures from containers assembled in cases which are moved seriatum into and out of position.
There has been increased concern for the container industry to encourage recycling of containers. For containers, such as beverage bottles having screw-off or twist-off closures, the consumer has been urged to return the metallic caps or closures associated with the bottles by replacing the caps on the bottles. The bottles are returned in cases to the bottling plant, but before the bottles can be cleaned and prepared for refilling, it is necessary to remove any metallic caps from the returned bottles. A problem of removing such closures efficiently is enhanced by the fact that millions of bottles are returned for recycling annually. Thus, a quick and easy removal of such closures is desired to reduce the bottle reclamation costs for the bottling industry.
In the prior art, there have been various ways proposed to remove the closures from containers as they pass singly along the bottling lines. One such way includes the use of an Archimedean screw passing through an internally threaded bush or nut and a jaw means on the end of the screw for gripping closures. Such a device is operated by fluid pressure and includes the use of hold-down pads to secure the container against rotation during the unscrewing operation, i.e. when the screw moves in the nut to cause rotation of the jaws to remove screw-off closures, as shown in U.S. Pat. No. 2,130,317, granted Sept. 13, 1938. Various other methods have also been tried which pierce or puncture the container closure to facilitate closure removal. Piercing of the metallic cap by a needle and forcing compressed air into the container to facilitate removal of the closure is shown in U.S. Pat. No. 3,587,208, granted June 28, 1971. Insertion of a blade into the closure and rotation thereof to remove a closure is shown in U.S. Pat. Nos. 3,520,102, granted July 14, 1970 and 3,775,829, granted Dec. 4, 1973. Screw-off caps can also be removed by the use of rotating impact rollers which contact the outside surface of the closure, as shown in U.S. Pat. No. 3,807,134, granted Apr. 30, 1974 and by the use of an endless moving belt, as shown in U.S. Pat. No. 3,845,605, granted Nov. 5, 1974.
In order to more efficiently remove screw-off closures from the millions of returned containers, it is known in the art to remove the closures while maintaining the containers in their cases. Such in-case decapping of containers obviates the need to remove each container from a case and to place it onto a bottling line to remove the closures from the containers singly. Such prior art in-case decapping methods and apparatus include moving a case of containers into position beneath a decapping apparatus having multiple head units which move vertically down onto containers in a case to facilitate removal of closures from all containers simultaneously. Such mechanisms include sensing devices for counting bottles and checking bottles to see if they are free of closures and for determining alignment or misalignment of bottles, and ejecting means for disposing of the closures from the head units and means for collecting such removed closures. Such mechanisms, however, may also include a large and/or complex gearing arrangement to facilitate vertical movement and rotation of the multiple head units. Repairs or replacement of a single head unit in the mechanism may, thus, be difficult. Additionally, the decapping apparatus may not be easily adjustable to accommodate various size closures and cases containing various numbers of containers per case.
Removal of closures from containers while in their cases has been proposed in various ways including piercing a closure with two pins and causing rotation of the closure while securing the container against rotation with a holding sleeve, as shown in U.S. Pat. No. 3,589,103, granted June 29, 1971. Still another device uses two continuous moving belts positioned on opposite sides of the closures of the containers to cause removal of the closures, see U.S. Pat. No. 3,852,867, granted Dec. 10, 1974. A fluid pressure gripping device of U.S. Pat. No. 3,686,824, granted Aug. 29, 1972 grips the closures of each container with a piercing pin and a holding sleeve having an inflatable element. Rotation of the device removes the closure and a subsequent reduction of pressure deflates the holding sleeve to eject the removed closure from the gripping device. U.S. Pat. No. 3,803,795, granted Apr. 16, 1974 shows the removal of closures from containers without the need of holding the containers by the use of a continuously rotating cup-shaped device which fits over the closure of a container and causes removal of the closure by engaging with the serrations of the closure.
There still exists a need, however, for an apparatus and method of removing twist-off closures from containers being transported in cases along a return case conveyor system in a bottling plant that is low in cost and can easily and inexpensively be installed on an existing return case conveyor in a bottling plant bottle return area. Such a device should have components that can be changed to accommodate various size closures and cases containing various numbers of bottles per case. Contact with the container, especially at the neck area, should be limited or avoided to prevent marring of the container finish and excessive wearing of any advertising on the container. Yet sufficient unscrewing torque must be provided to break any temporary bond or seal securing a closure to a container. It is also desirable to incorporate safety features to prevent damage to the apparatus due to improperly located containers or damaged cases.